DNA, or deoxyribonucleic acid, is the most important molecule of living organisms. It contains the genetic instructions used in the development and function of living creatures. DNA stores all the genetic coding that is required to fully develop a life form. It also holds all the instructions for specific cell creation. DNA is the blueprint of life. It is DNA that determines factors such as eye and hair color. Human DNA consists of about 3 billion bases, and more than 99 percent of those bases are the same in all people.
The Discovery of DNA
Many scientists had a hand in the discovery of DNA. The invention of new scientific and medical equipment and procedures made it possible to better identify the molecule we now recognize as DNA. The first isolation of DNA was in 1869 by a Swiss physician named Friedrich Miescher. He discovered a microscopic substance in the nuclei of pus cells on discarded bandages. He named the substance nuclein. In 1919 a Russian biochemist named Phoebus Levene isolated the base, sugar and phosphate nucleotide unit. He did not recognize that the chain was long and complex and believed that the same pattern was repeated over again in the same order in all DNA. New technology allowed the first x-ray image of DNA to be captured by William Astbury in 1937. The x-ray showed that DNA had a regular structure. DNA continued to be studied carefully and many scientists such as Oswald Avery, Colin MacLeod, Maclyn McCarty, Alfred Hershey and Martha Chase added to the scientific understanding of DNA by discovering its genetic properties.
In May 1952, Rosalind Franklin and Raymond Gosling took an X-ray diffraction image that lead to the discovery of what we now know as DNA’s double helix shape. James D. Watson and Francis Crick suggested what is now accepted as the first correct double-helix model of DNA structure in the journal Nature in 1953. Another article appeared with these written by Maurice Wilkins on the structure of DNA. After the death of Rosalind Franklin in 1962, Wilkins, Watson and Crick received a Nobel Prize in Physiology or Medicine for their “discovery” of the double helix DNA molecule.